Most plants get energy from the sun and nutrition from the soil, but nature always has exceptions. A handful of plants have evolved the ability to digest animal protein: the carnivorous plants. While the notion may conjure images of remote tropical jungles, they can be found worldwide, even as far north as the tundra. The most famous of these, the Venus flytrap, lives only in the Carolinas! There are several that can even be found here in Wareham.
Carnivorous plants have evolved their unique abilities to find nutrition in nutrient-poor soils. They almost all live in waterlogged places. Organic matter decomposes very slowly underwater, and even more so in low-oxygen environments. Most bacteria need oxygen to perform their chemical reactions, just like fire needs oxygen to burn. The still water in bogs gradually loses its oxygen, and elements like carbon and nitrogen become locked up in peat and are inaccessible to most plants. Though harsh, these environments are home to rare and unusual plants.
Three groups of carnivorous plants can be seen in Wareham: bladderworts, pitcher plants, and sundews. This time of year, the easiest to see are the sundews; we’ll visit the others another time. Sundews, the genus Drosera, are like a slow-motion Venus flytrap, to which they are closely related. These small plants grow as a rosette, meaning that all the leaves grow from a central hub, like spokes on a wheel. Depending on the species, their leaves are either round, flat pads or long, grassy blades. These leaves are covered in small tentacles, which have glands that secrete either a sweet attractant or sticky mucilage. These substances give the sundew its name, as they glisten in the sunlight like a morning dew that never burns off.
These plants exhibit thigmonasty, meaning they are triggered by touch. The process is still only partially understood by science. When an insect lands to feed on the sweet liquid, the plant releases a hormone called auxin, which triggers rapid growth on one side of the tentacle, causing it to bend towards the center of the leaf. Gradually, the insect is engulfed and smothered in the sticky dew. Through the use of digestive enzymes and fungal partnerships, the insect is dissolved and ingested by the leaf. Eventually, the leaf reopens and is ready to trap again.
To spot these plants, look in sphagnum moss in boggy areas alongside streams, pond shores, and cranberry bogs. You’ll need to look closely, as they are usually only an inch or two across. Despite their small size, they are quite beautiful, with bright reds and greens providing a striking background for their glistening dewdrops. When you find one, there are likely many more nearby. Look for folded leaves to see where they have caught their prey. While you are safe from their carnivorous jaws, tread carefully, as these are sensitive environments.
By Justin Cifello
Wareham Land Trust Member and Volunteer